The present invention relates to a self-propelled machine for stabilizing tracks laid on ballast.
After repairs to the geometry of tracks, usually performed by means of tamping, aligning, and leveling machines, ballast settling conventionally occurs when the first trains pass; this settling is characterized by the migration of the crushed rock from the tamping region below each tie towards the upper part of the ballast in the intermediate region and towards the heads which lie externally with respect to said ties.
The enclosed FIGS. 1 and 1a schematically show said settling of the crushed rock which, due to the passage of the trains C on the track BI, migrates partially from the tamping region A below the ties T.sub.1, T.sub.2 . . . , T.sub.n in the upper part of the region B of the ballast which lies between two consecutive ties T.sub.1 -T.sub.2, and simultaneously, due to the hunting of the trains, towards the head regions C (FIG. 1a).
This settling produced by the migration of the crushed rock in the specified direction is followed by a variation in the level of the track in the longitudinal plane (change in the elevation of the rolling plane) and by a deflection of said track in the transverse plane or plane of arrangement (lateral deflection and/or misalignment), with a consequent alteration of the geometric characteristics of the track which is not compatible with the travel comfort and is correlated to the transit speed of modern trains.
The operations for restoring and regenerating railroad ballasts must therefore be followed by one or more track stabilizing operations aimed at preventing the uncontrolled settling of the regenerated ballast produced by the passage of trains.
Track stabilizing machines already exist for this purpose which act by vibration on said track but have several disadvantages, the main one being the generation of intense stresses on the systems for coupling the rail and the tie to each other and the more or less extensive modification of the track laying geometry. Moreover, these conventional machines are necessarily limited in their use, since the intensity of the shaking vibrations transmitted by said machines to the track causes stability problems for the static structures lying adjacent to the railroad, particularly to buildings, bridges, overpasses, underpasses, level crossings, and to the moving elements of tracks such as switches, junctions, and the like, so that said conventional machines are unable to perform adequate work over entire stretches of the railroad.